Rotary pump



Oct. 20, 1959 Filed March 13, 1956 O. MAISCH ROTARY PUMP 2 Sheets-Sheet 1 Oct. 20, 1959 o. MAISCH 2,909,124

ROTARY PUMP Filed March 15, 1956 2 Sheets-Sheet 2 h I ll United States Patent ROTARY PUMP Oliver Maisch, Chicago, Ill.

Application March '13, 1956, Serial No. 571,251

2 Claims. (Cl. 103-126) The present invention relates to small motor driven pumps and has for its object to produce a smiple and inexpensive pump which can be cleaned quickly andeasily so as to be kept in a thoroughly sanitary condition; thus guarding against contamination of liquids handled thereby.

Aside from using in the construction of a pump materials that are not harmful to liquids passing through the same, one of the most important factors is the ability to dismantle the same so completely that every surface that touches the liquids can readily be exposed. This may be made possible through so constructing the pump that it may be completely dismantled and again assembled.

One of the objects of the invention is therefore to create such a structure that dismantling and assembling may be done entirely by hand, without reliance on tools.

The various features of novelty whereby the invention is characterized will hereinafter be pointed out in the claims; but, for a full understanding of the invention and of its objects and advantages, reference may be had to the following detailed description, taken in connection with the accompanying drawings, wherein:

Fig. 1 is an end view of a preferred form of my improved pump mounted on a motor;

Fig. 2 is a side view of the pump and motor;

Fig. 3 is a section through the pump, on a larger scale, on line 3-3 of Fig. 1;

Fig. 4 is a section on line 44 in Fig. 3, showing only the pump, proper;

Fig. 5 is a section through the pump, on the same scale as Fig. 3, on line 5-5 of Fig. 1;

Fig. 6 is a view similar to Fig. 4 with the gears and sealing ring omitted;

Fig. 7 is a view of a motor driven centrifugal pump, the pump being a longitudinal axial section and the motor being a side elevation; and

Fig. 8 is an end view of the structure shown in Fig. 7.

Referring to Figs. 1-6 of the drawings, 1 and 2 are two stainless steel discs lying flat against each other and forming a pump housing. A third disc 3 serves a backing plate; disc 2 lying between discs 1 and 3. Disc 2 is shown as being thicker than the other two discs so that it may be deeply recessed in the face in contact with disc 1 to create the pump chamber 4 of which the latter disc forms the cover. This pump chamber is of the conventional gear pump type, comprising two overlapping sections 4 and 4 Disc 1 contains two openings, 5 and 6, which are respectively, the inlet and outlet for the gear chamber.

In chamber 4 are two gears 7 and 8. Gear 7 is mounted for rotation about a little stub shaft 9 rising from the bottom of said chamber and extending almost to disc 1. Gear 8 surrounds a shaft 10 that extends into the pump housing through an opening 11 in disc 3 and an opening 12 in disc 2 in registration with the latter opening. Openings 11 and 12 are so designed that there is formed between disc 3 and the pump chamber a pocket 12 partially closed at the ends by discs 2 and 3.

Shaft 10 is provided with a radial pin 14 that fits slidably in a groove 15 opening into the axial bore 16 in gear 8. Shaft 10 is pinned to motor shaft 17 so as to rotate therewith. Fitting in pocket 12 is an elastic packing ring 18, preferably in the form of an endless annular trough; the open side of the trough facing the pump chamber. This packing ring forms an effective seal around shaft 10 and against disc or plate 3 to close the only outlet through the rear or bottom of the pump cham her.

In the face of disc 2 that engages disc 1 is an annular groove 19 encircling the pump chamber. In this groove is an elastic packing ring 20 which forms a seal between these two discs.

In openings 5 and 6 are fixed corresponding ends of nipples 21 and 22, respectively. Tubes 23 may be attached to these nipples when the pump is in use. In the absence of such tubes, caps 24 may be snapped over the ends of the nipples to keep out foreign matter.

In outlet nipple 22 is a check valve. This consists of a ball 25 cooperating with a valve seat on the inner end of a short sleeve or bushing 26 frictionally held in the inner end of the nipple. The grip on the sleeve is increased by an elastic packing ring 27 fitted into an external circumferential groove in the sleeve. The ball is normally held against the seat by a spring 13.

The entire pump assembly is clamped together and to an adapter 30 mounted on the casing of a motor by two screws 32 having wing heads 33. Each screw is also provided with an integral collar 34 which bears against-the outer face of disc 1 when the screws are tightened. The holes in the three discs through which the screws pass are simple bores so that, once the screws are freed from the adapter, the entire pump comes apart; only shaft 10 remaining attached to the motor. Since pin 35, which secures shaft 10 to the motor shaft, is removable shaft 10 may be detached from the motor shaft for cleaning or other purposes.

It will be noted that the pump is eccentrically mounted with respect to the motor shaft. To ensure that the discs can be assembled only in the proper angular positions relative to each other and the adapter, the latter is provided with a pair of short dowel pins 36 that project from the face thereof far enough to pass through holes 37 in disc 3 and into registering holes 38 in disc 2. Disc 3 can be applied in only one way, namely, with opening 11 registering with opening 12 in disc 2 and with shaft 10. The identifying words Out and In, adjacent to the outletnipple and the inlet nipple respectively, aid the assembler in applying disc 1, knowing that the outlet must be at the left or, more certainly, that the words must not be upside down. Pins 36 also serve accurately to align the pump with the motor shaft, making it unnecessary for the screws 32 to perform that duty.

After the pump is detached from the motor the two gears may be caused to drop out by simply turning disc 2 over to bring the gears on the under side, and sealing members 18 and 20 may easily be detached. Also, the inner end 26 of bushing or sleeve 26 in outlet nipple 22 is preferably so shaped that this element may be lifted out with ones fingers to permit the ball valve and spring to spill from the nipple.

It will thus be seen that the pump may quickly be so completely separated into its individual elements that cleaning and sterilizing of the pump may be carried out easily and effectively; dismantling and reassembling requiring no tools. Also, because the adapter is in the form of a ring, ready access is had to shaft 10 for cleaning purposes after the pump is detached. Furthermore,

because of the structural characteristics of the pump,

sterilization may be achieved by simply causing it to pump sterilizating fluids for a short period.

The gear pump heretofore described meters liquids and is therefore well adapted to pump liquids in small quantities, even a drop at a time.

Where extreme accuracy in the measurement of liquid is not essential, but the volume handled in a given time is important, the same structural features that serve to provide easy and rapid demountability and cleaning may be employed in a centrifugal pump; capacity being greatly increased without increasing the size of the pump. Thus a centrifugal pump, the housing of which is not more than two and a quarter inches in diameter, may be used in connection with soft drink fountains to dispense fruit juices or other liquids, as needed; or it may be used to dispense, transfer or circulate liquids of any kind, under sanitary conditions, anywhere and for any purpose.

Such a centrifugal pump is shown in Figs. 7 and 8. Referring to these figures, 40 is an adapter ring secured to a motor casing 41 by screws 42 passing through the ring and some spacers 43 and into the casing. The outer fiat face of the ring contains a central depression 44 in which is seated a disc 45 corresponding to the disc or backing plate 3 in the other pump.

The pump housing comprises two members 46 and 47 that meet in a plane parallel to the plane .of ring 40 and shaped to provide between them a pump chamber 48 which is cylindrical in shape. The inlet to the pump chamber is through the center of housing 46, namely through an axial tube or nipple that flares in diameter at the pump chamber; this element being 46*. The outlet from the pump chamber is through a tangential tube or nipple 47 associated with housing member 47, because the pump chamber, proper, is shown as being located wholly in that member.

Members 45, 46 and 47 are clamped together and to the adapter ring by two screws 49 similar to screws 32 in the other form of pump; the main difierence being that the screws do not and need not pass through the backing plate. Dowel pins 50 extend from the adapter ring into holes in housing member 47.

Housing member 47 has four radial ears '52 into two of which the dowel pins extend; whereas the other two lie behind and register with two similar cars 53 on housing member 46; screws 49 passing through cars 53 and the corresponding ears on member 47.

Between members 46 and 47 is a large packing ring 54 similar to ring 20 in the other pump; to eifect a tight seal between the two housing members.

Within the pump chamber is a conventional impeller 55 provided with an axial bore out of which opens an internal, longitudinal groove 57. As in the other pump, member 47 and backing plate 45 are provided with-composite openings coaxial with the bore in the impeller; the shaping thereof being such as to provide a pocket 58, partially closed at one end by the backing plate 45 and at the other end by a shoulder in that part of the opening that lies in member 47. In this pocket is a flexible packing ring 60.

A shaft 61, which may be the motor shaft, extends through said composite axial opening, with the packing ring 60 snugly fitting around the same, and into the bore in the impeller. On shaft 61 is a radial pin 62 which enters groove 57 in the impeller and locks the impeller to the shaft so as to compel them to rotate in unison, while permitting the impeller to slide on and off the shaft in assembling the pump on the adapter ring and in detaching the pump and dismantling it.

In this form of the invention, as in the other, only two manually operable screws need be removed to detach the pump from the adapter and completely dismantle it with the exception of the two flexible packing or sealing elements which maybe lifted outwith ones fingers. The two pumps are exactly alike so far as sanitation is concerned.

While I have illustrated and described with particularity only two forms of my invention, I do not desire to be limited to the exact details so shown and described; but intend to cover all forms and arrangements coming within the definitions of the invention constituting the appended claims.

I claim:

1. In a sanitary pump adapted for use in pumping beverage syrups and the like, a support having a substantial access opening therethrough and a mounting face perpendicular to such opening, a sectional pump housing and a plurality of thumb screws extending through such housing to hold the same removably in assembled relation against said face of said support, said pump housing comprising a back plate engaging said support, the middle plate engaging said back plate and a front plate engaging said middle plate, sealing means between said front plate and said middle plate, and recessed into one of said plates, and defining a substantial annular area, the face of said middle plate that is adjacent said front plate having two overlapped circular recesses therein located Within said area and adapted to receive pump gears in meshed relation, and also having inlet and outlet chambers located within said area and opening into said circular recesses on opposite sides of intersecting portions thereof, a stub shaft mounted permanently in one of said circular recesses on the axis thereof and terminating short of the adjacent face of said front plate, said middle plate also having an opening therethrough centered on the other circular recess, said last-mentioned opening having an enlarged portion defining an annular pocket opening through the face of said middle plate that is engaged with said back plate, said back plate having an opening therein coaxial with the opening in said middle plate, said front plate having inlet and outlet ports therein connecting, chambers of said middle plate, a first pump gear in said one circular recess supported removably on said stub shaft, a second pump gear in the other circular recess, said second gear having a central bore with a keying element therein, a-drive shaft mounted in a fixed position and projecting through the access opening in said support, and through the openings in said back plate and said middle plateand removably into the central bore'of said second gear, said drive shaft having a keying element thereon engaging the keying element of said second gear, and an annular flexible sealing member of U-shaped cross section removably disposed in the pocket of said middle plate about said shaft and having the open edge of said U-shaped cross section facing toward said second gear, the opening in said back plate being smaller than said pocket so that said back plate holds said U-shaped sealing member in position on said shaft against pumping pressure that is applied thereto.

2. In a sanitary pump for pumping edible syrups and the like, a support, a drive shaft extending through said support, a pump casing comprising front and back plates and a middle plate located therebetween, thumb screws extending through said plates and removably securing the same in assembly relation and in position on said support, said front plate and said middle plate having engaging faces, compressible sealing means removably recessed into one of said engaging faces and engaging the other of said faces to surround and define a substantial area located in spaced relation to the outer edges of said faces, said back plate being disposed between said middle plate and said support, said middle plate having a pair of intersecting circular recesses formed therein within said area and in the face thereof that opposes said front plate, said recesses being adapted to removably receive a pair of pump gears in meshed relation, said middle plate and said front plate having related inlet and outlet passages communicating with said circular recesses on opposite sides of the intersecting portions of the circular recesses, one of said circular recesses having a stub shaft permanently respectively, with said inlet and outlet mounted centrally thereof and terminating short of the adjacent face of said front plate, a first pump gear removably supported on said stub shaft Within said one circular recess, a second gear disposed in the other circular recess, said middle plate and said back plate having aligned openings therein through which said drive shaft extends in spaced'relation to such openings, said drive shaft extending into driving relation with said second gear and said second gear being removably related to said drive shaft, said middle plate having the opening therein enlarged adjacent to said back plate to provide an annular pocket, an annular sealing member disposed in said pocket, said sealing member being of U-shaped cross section with the open side of said U facing toward said second gear so as to be exposed to pumping pressure, said annular sealing member being held in position in said pocket by said back plate.

References Cited in the file of this patent UNITED STATES PATENTS 237,764 Medden Feb. 15, 1881 1,346,960 Hurd July 20, 1920 1,475,676 Bell et al Nov. 27, 1923 1,525,884 Plurnmer Feb. 10, 1925 1,531,904 Dinesen Mar. 31, 1925 1,592,267 Hamer July 13, 1926 1,595,688 Porter Aug. 10, 1926 1,672,257 Heitz June 5, 1928 2,176,388 Bochmann Oct. 17, 1939 6 Otken Feb. 6, Dietzel Mar. 12, Doeg July 9, Hartman June 10, Marco June 15, Brady Aug. 14, Pezzillo Dec. 23, Bakewell Sept. 13, Brant Aug. 5, Mapes Nov. 18, Maisch Nov. 25, Maisch Nov. 25, Jerome Dec. 16, Browne Jan. 20, Neilsen Feb. 17, Collura Apr. 7, Dale et a1. Apr. 21, Funk Apr. 28, Thomas June 23, Osborne ..Oct. 13, Framhein Nov. 17, Montgomery et al. July 20, Namur Mar. 12, Miller June 18,

FOREIGN PATENTS Australia Oct. 6, Germany May 27, France Mar. 3,

France Nov. 10, 

